Our overall objectives remain to provide basic information on the biochemistry of the cell membrane and of membrane associated phenomena in the most thoroughly studied of organisms, Escherichia coli. To do these, we depend strongly on genetic techniques including the isolation and characterization of mutants and the movement of genes from cell to cell. Membrane associated phenomena that we expect to study during the next year include: (a) Cation transport systems for magnesium, manganese, calcium and potassium; (b) Isolation of hypothetical cation carrier molecules (ionophores); (c) Cell-free purification of mercury-reducing and mercurial-reducing enzyme systems under the control of genes found on R factors; and (d) A genetic-biochemical approach to the coupling of energy metabolism (respiration and oxidative phosphorylation) to active transport.